/**
*      author: Y_Yao
*      created: 2024-10-24 20:14:23
**/

#include<bits/stdc++.h>

using namespace std;
using LL = long long;
const LL LLINF = 1e18;
const int INF = 0x3f3f3f3f;
const int N = 2e5 + 7;
int a[N],diff[N];
int n;

void solve()
{
    memset(diff,0,sizeof diff);
    cin >> n;
    for(int i = 1;i <= n;i++)
    {
        cin >> a[i];
    }

    for(int i = 1;i <= n;i++)
    {
        int left = i - a[i] + 1;
        int right = i + a[i] - 1;
        left = max(1,left);
        right = min(right,n);
        //if(right - left + 1 > i) continue;
        diff[left] += 1;
        diff[right + 1] -= 1;
    }

    int ans = 0;
    for(int i = 1;i <= n;i++)
    {
        diff[i] = diff[i-1] + diff[i];
        if(diff[i] == n) ans++;
    }

    cout << ans << endl;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);

    int t = 1;
    cin >> t;
    while(t--)
    {
        solve();
    }
    return 0;
}